According
to Genesis 1:27, "God created man in His own image." OK, but what about all
the other intelligent, cosmic inhabitants? Well, Hollywood has taken
care of that. It has created aliens in man's image.
It's hardly
a major revelation to point out that most movie aliens bear a strong likeness
to humans. Typically, they have well defined heads, and two of everything else
of note: eyes, nostrils, arms and ambulating legs. They're strongly
anthropomorphic, and if some of these hairless little louts moved into your
neighborhood, you'd probably get around to inviting them to dinner.
Aliens that
resemble us are convenient for
storytelling, because you already know how to read their intentions. Their
behavioral cues are familiar, and you can tell if their game plan is to be
amorous or aggressive. (In most movies, these are their only options.)
But is
there reason to think that actual
aliens, from a star system a thousand light-years away, would be similar in
appearance to the evolved apes that we now call Homo sapiens? Some
scientists, such as Cambridge University paleontologist Simon Conway Morris,
think there is. After all, there's a phenomenon in nature known as convergent
evolution. It's the tendency of evolutionary processes to find similar solutions
to any given environmental challenge. For instance, if you're a predator whose existence
depends on catching lunch day after day, you probably have two eyes with
overlapping fields of view. Stereo vision is a real plus for pouncing on prey.
Similarly,
for marine creatures that have a need for speed, the laws of hydrodynamics
favor being long, thin, and oh-so-streamlined. Convergent evolution has ensured
that barracudas are shaped like dolphins, even though the former are fish and
the latter are mammals. Being built like a torpedo just works better.
This
mechanism is often invoked by sci-fi writers as a convenient explanation for
why so many of their alien protagonists resemble earthlings brushed with battery
acid. (Even the language - "convergent evolution" - which is so ponderously Latinate,
bespeaks academic merit and scientific plausibility.)
As a consequence,
it's possible that a hominid shape is the best body plan for sentient beings on
any world, and no doubt Tinseltown would be pleased to learn that its rubber-suit
aliens are good approximations to the real thing. But I'll bet you dollars to Devil
Dogs that any extraterrestrials we detect won't be muscular guys with deep
voices and corrugated foreheads, or even big-eyed, hairless grays. And that's
not because such
creatures couldn't exist. Rather, it's because of the timescale for
non-biological evolution.
Here's the
deal: it's widely believed that aliens are out there. But proof requires the
following: Either aliens need to visit Earth (don't start!) or we need to detect
them with our telescopes - for example, in one of our SETI experiments. In
either case, we're dealing with beings whose technological level is beyond
ours. That should be obvious because, after all, we're not yet at the point
where we can engage in interstellar travel. And as for getting in touch via
signals, well we're not blasting continuous, powerful transmissions to lots and
lots of other worlds. We don't have either the money or the equipment. Maybe
someday.
In fact, no
matter how we find them - in the backyard, on the radio, or through our
telescopes - any detected aliens will be at least a century beyond us. More
likely, a millennium or more.
OK. But if
they're beyond our technical level, what can we say about their appearance? Well,
using our own experience as a guide, consider a human development that seems
likely to take place sometime in the 21st century: we'll invent machine
intelligence. Some futurists figure this dismaying development will take
place before 2050. Maybe it will take twice that long. It doesn't matter. By
2100, our descendants will note that this was the century in which we spawned
our successors.
So here's
the point: Since any aliens we detect are ahead of us, they've already done
this; they've made the transition from biological to engineered intelligence,
and left behind the quaint paradigm of spongy brains sloshing in salt water.
In other
words, and despite what "The X-Files" would have you believe, the sort of humanoid,
fleshy aliens that routinely populate fiction are very unlikely to be the type
we will discover. Instead, they'll be machines. Dollars to Devil Dogs.
All of
which reminds me: the next time your neighbor claims that extraterrestrials
have once again hauled him out of his bedroom for distasteful
experiments, ask whether the abductor was a protoplasmic being with four
limbs, or some sort of complex hardware. I think I already know what the
answer will be, and it's the wrong one.
Seth
Shostak's latest book is "Confessions of an Alien Hunter"
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